The fifth wheel of a truck tractor is designed to hook a trailer securely to the tractor. A pin on the trailer slides into a locking mechanism which latches to lock the trailer to the tractor. A release handle is pulled by the trucker to disengage the trailer.
The Jost brand of safety catch release handles, is not simply pulled. Instead, the handle must be raised upward with a force of about twenty pounds, then moved cab-wards, then finally pulled outward to release the trailer. If this sequence is not followed, a notch on the handle snags and prevents accidental or mischievous disengagement. Use of both hands is practically impossible.
Release handles must be used in rain, snow, dark, or storm. The lift-forward- and cabward motion of a Jost release handle can be difficult for even a strong, long-armed trucker to perform. A smaller trucker must wedge himself or herself under the trailer, which is hazardous in slippery weather.
The Occupational Safety and Health Administration (OSHA) Technical Manual “Evaluation of Lifting Tasks: NIOSH Work Practice Guide for Manual Lifting,” provides a formula for two-handed lifting, which results in a maximum of approximately ten pounds maximum lift in the situation above. No OSHA guidance could be found for a single hand, but it quite reasonably would be lower. Thus the Jost release handle may require a lifting force far in excess of OSHA guidance.
Examples of many release handle aids are found in the prior art. U.S. Pat. No. 6,935,664 granted Aug. 30, 2005, discloses a foot-operated release lever aid. U.S. Pat. No. 4,251,089 issued Feb. 17, 1981, discloses a force-multiplying lever aid. U.S. Pat. No. 7,591,476 issued Sep. 22, 2009, and U.S. Pat. No. 7,347,467 issued Mar. 25, 2008, disclose multi-purpose release mechanisms.
The upward-cabward-outward motion required by the Jost release lever is not addressed by the prior art, which only provided outward pulling.
It is an object of the invention to provide the upward-cabward-outward forces needed to operate a Jost fifth wheel safety catch release mechanism in a compact form.